A modern fire engine is usually a multi-purpose vehicle carrying professionals and equipment for a wide range of fire-fighting and rescue tasks. The fire engine may have several methods of pumping water onto a fire, such as delivering water obtained from a fire hydrant through hoses and, in some cases, a pumping “monitor” (also known as a cannon or a deck gun). Some fire engines also have an onboard water reservoir from which water is pumped.
A fire engine typically includes a pump panel having a plurality of selectable valved pump outputs, the valves being controlled by electric actuators. In some arrangements a single, common pump supplies fluids to all of the valves simultaneously. The pump, in turn, is coupled through a power take-off (PTO) to a power source such as a prime mover engine of the fire engine. A governor may be provided to control the speed of the prime mover engine, in turn controlling the manifold pressure of the pump.
In some cases the temperature of the water being passed is monitored when the pump is maintaining a particular pressure with relatively low quantities of fluid flow. Some of the water is returned to a water reservoir, thereby minimizing heating of the water.
A drawback of the aforementioned pump arrangement is that operators must continuously monitor the overall system to modify valve positions, manifold pressure, and/or the power source in response to changing open or closed conditions of the output valves. A control system is needed to reduce the amount of attention and interaction required of the operator so that they are free to perform other tasks. Such a control system also preferably minimizes errors due to operator inexperience.